CONTENTS. 



ABSORPTION SPECTRA. (The influence of temperature and magnetisation on selective). 

 578. II. 734. III. 83'.). 



— (Tiie) of the compounds of the rare earths at the temperatures obtainable with 

 liquid hydrogen and their change by the magnetic field. 592. 



ACIDS (The action of concentrated sulphuric acid on glycerol esters of saturated mono- 

 basic fatty). 855. 



ADSORPTION (On the) of the smell of muscon by surfaces of dift'erent material. 116. 

 Continued. 120, 



AIR-TEMPERATURE (The analysis of frequency-curves of the). 309. 



ANALOGON (The) of the Cf. of Kummer in seven-dimensional space. 503. 



Anatomy. J. W. van Wijhe : "On the existence of cartilaginous vertebrae in the 

 development of the skull of birds". 14. 



— J. W, Langklaan : "On the development of the Corpus Callosum in the human 

 brain". 344. 



— S. J. DE Lange : "On ascending degeneration after partial section of the 

 spinal cord". 386. 



Anthropology. L. Bolk: "Is red hair a nuance or a variety". 321. 

 Astronomy. W. de Sitter : "On periodic orbits of the type Hestia". 47. 



— W. de Sitter: "On some points in the theory of Jupiter's satellites". 95. 



— J. Stein : "|3 Lyrae as a double star". 459. 



— J. C. Kapteyn: "On the mean star-density at diti'erent distances from the 

 solar system". 636. 



— W. DE Sitter: "On the masses and elements of Jupiter's satellites and the 

 mass of the system". 653. (Continued), 710. 



AXES of symmetry (On the permissible orders of the) in crystallography. 408. 



BAKHUYZEN (e. F. VAN DE SANDE) V. SaNDE BaKHUYZEN (E. F. VAN DE). 

 BAKHÜYZEN (H. G. VAN DE S A N D E) V. SaNDE BaKHUYZEN (H. Gr. VAN DE). 



BARRAU (j. a.). The extension of the configuration of Kummer to spaces of (2p — 1) 

 dimensions. 263. 



— The analogon of the Cf. of Kummer in seven-dimensional space. 503. 

 BATAVIA (liegistration of earth-currents at) for the investigation of the connection 



between earth-current and force of earth-magnetism. 512. 2nd part. 782. 



59 



Proceedings Royal Acad. Amsterdam. Vol. IX. 



